The manufacture of a semiconductor element includes a step of dividing a wafer into element chips, and a method in which separation grooves are formed with a cutter, dicer, or the like and the pieces snapped apart has been used to divide these element chips. A method has been proposed in recent years in which a laser beam is used instead of a cutter or dicer to form separation grooves or the like, and the chips are then broken apart, but with a method in which a wafer is heated and melted by being irradiated with a laser beam, the places that are melted and then re-solidify become discolored, and this decreases the brightness of a light emitting element, so a method has been proposed in which a pulsed laser beam with a short pulse width is used to work the wafer. Using a pulsed laser beam with a short pulse width allows working to be performed that is free of discoloration because it involves multiphoton absorption rather than melting, so there is less of a decrease in the brightness of a light emitting element.
As shown in FIG. 12, a method that has been proposed for dividing element chips using a pulsed laser beam with a short pulse width, in which a modification region 41 is formed by laser irradiation in a region corresponding to an intended dividing line inside of a substrate 40 provided with a semiconductor layer 42, and the chips are broken along this line (JP-2008-6492-A).
Also, as shown in FIG. 13, another method has been proposed in which a plurality of levels of modified components 51 are formed by laser irradiation inside of a substrate 50 provided with a semiconductor layer 52, and a continuous groove 53 is formed by laser irradiation in the surface of the substrate 50, so that the semiconductor light emitting elements are separated from a separation plane along the groove 53 and the plurality of levels of modified components 51 (JP-2008-98465-A and JP-2007-324326-A).